A Republican in a hotly contested Arizona congressional race fought back on Tuesday against an attack ad by gun control advocates, saying she has always favored barring stalkers from owning guns and dismissing suggestions to the contrary as “vile tactics.”

Martha McSally, a retired Air Force colonel and combat pilot, is challenging Democrat Ron Barber, a former aide to Gabrielle Giffords, the then-congresswoman seriously injured in a deadly 2011 shooting rampage outside a Tucson supermarket.

Barber narrowly beat McSally in a November 2012 vote after winning a special election following the shooting that killed six people and wounded 13. He and McSally are now vying for a redistricted seat.

Giffords, who was shot through the head, set up a gun control advocacy group, Americans For Responsible Solutions, which began running a television ad in Arizona last week criticizing Barber’s Republican rival.

The spot shows a woman whose 19-year-old daughter was stalked and killed by an ex-boyfriend, and who says McSally opposed making it harder for stalkers to get firearms. On Tuesday, the group said it was pulling the ad from screens.

McSally’s campaign spokesman, Patrick Ptak, said the makers of the ad used “vile tactics” and never once asked for her views on the issue. He said McSally had been a victim of stalking herself and knew first-hand what the fear was like.

“Her experiences guide her thoughts, and she has always held that convicted stalkers should be prohibited from obtaining firearms in all cases,” Ptak said in a statement.

“Instead of looking to distort the truth to score cheap political points, Ron Barber’s political allies should have done their homework first.”

Federal law does not preclude individuals convicted of stalking from owning a firearm, although it does bar those convicted of domestic abuse from having guns. A bill being considered in Congress seeks to close the “stalker gap.”

Americans For Responsible Solutions accuse McSally of being “in lockstep with the corporate gun lobbyists who support her.”

The Republican candidate called on Barber to denounce the ad in person.

“For an outside group to tie me to the tragic occurrence of a stalker killing his victim, is not only personally offensive, it’s degrading to all women and victims who have experienced this pain,” McSally said.

(The story corrects typo in name in second paragraph, injuries to Giffords in fourth paragraph.)